1. Field of the Invention
The present invention relates to a vehicle hood.
2. Description of the Related Art
A vehicle hood is already known that comprises a skin and a lining that are superposed. The skin is essentially plane and the lining includes a depression extending essentially in the transverse direction of the vehicle when the hood is mounted on the vehicle, the depression being located at the rear end of the hood and being shaped to co-operate with the skin of the hood to form at least one hollow body.
The lining is made of a thermosetting material such as sheet molding compound (SMC), while the skin is made of metal, such as aluminum.
The skin and the lining of the hood are connected together at their respective ends by adhesive and by crimping, and they are subsequently mounted on the vehicle.
Nevertheless, because of the intrinsic properties of the two types of material making them up, the skin and the lining behave very differently with respect to temperature. Thus, the hood tends to deform when the temperature increases as a result of differential expansion between the skin and the lining that together make up the hood. This is particularly troublesome when the bodywork passes through cataphoresis, during which the bodywork and the hood mounted thereon are immersed in a bath and then pass through a stove at very high temperature. While in the stove, the skin expands more than the lining, which is attached to the skin at each of its ends, thereby giving rise to deformation of the hood. In addition, if provision is made for adhesive to be cured while the hood is passing through the stove, the skin and the hood are held stationary relative to each other in a deformed configuration of the hood, and that is unsatisfactory since it is no longer possible to return the hood to its normal shape on cooling.
The problem of remanent deformation associated with differential expansion is analogous when the skin and the lining are made of other materials. In particular, the problem also exists for a skin made of steel and a lining made of thermoplastic material, except that under such circumstances, it is the lining that expands more than the skin.
What is needed, therefore, is a system, method and lining that overcomes one or more of the problems mentioned.